


Perfect Pureblood | Black Sister

by jellyrice101



Category: Harry Potter - J. K. Rowling
Genre: F/M
Language: English
Status: In-Progress
Published: 2021-02-12
Updated: 2021-02-11
Packaged: 2021-03-18 12:07:09
Rating: General Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 6
Words: 3,601
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29368239
Author URL: https://archiveofourown.org/users/jellyrice101/pseuds/jellyrice101
Summary: Cassiopeia Walburga Black, daughter of Orion and Walburga Black, twin of Regulus Arcturus Black, and younger sister of  Sirius Orion Black. Being apart of the Sacred 28 is never easy, especially when you could care less about blood status. Of course, no one could ever know Cassiopeia feels this way, but what happens when she falls in love? When she gets thrown into an arranged marriage with a man she does not love? Brave or Coward? Which will she be?All Rights of Harry Potter World to J.K. Rowling
Relationships: Cassiopeia Black/Jackson Avery, Regulus Black & Sirius Black, Remus Lupin/Cassiopeia Black, Remus Lupin/Original Female Character(s), Sirius Black & Original Female Character(s), Sirius Black & Remus Lupin & Peter Pettigrew & James Potter
Kudos: 1





	1. Chapter 1

Cast:

Phoebe Dynevor as Cassiopeia Walburga Black  
Born: 21 January 1961

Timothee Chalamet as Regulus Arcturus Black  
Born: 21 January 1961

Ben Barnes as Sirius Orion Black  
Born: 3 November 1959

James Norton as Jackson Avery  
Born: 19 February 1955

Andrew Garfield as Remus Lupin  
Born: 10 March 1960


	2. Goodbye Sirius

1 September 1971

Cassiopeia pov:

"Promise me you'll write?" a teary-eyed Cass asks her older brother.

"of course I'll write to my favorite sister," a smirking Sirius responds. Cass smiles a little and hugs her big brother goodbye.

"Goodbye brother," Regulus states trying his best not to show his sadness because 'you are a man in the Noble House of Black, we do not cry' father always says. To those passing by Reg may seem totally fine with his big brother leaving, but I know he is sad and scared for him.

flashback: the night before

It is around 10 pm and the 3 black children were sent up to bed at around 9 pm. After tossing and turning for the past hour I decide to go and knock on your twin's door. To my surprise, Reg is also very much awake. I go and lay next to him on his bed.

"I'm scared for Siri," I say.

"Me too" Reg responds.

After a couple of seconds of silence, I decide to say the thing everyone is thinking but too scared to admit "He's not going to be sorted into Slytherin is he?"

"No... he's too brave" Regulus says sadly.

Brave... Sirius Orion Black is brave to stand up to Orion and Walburga Black. I mean I am my father's favorite and he scares the living shit out of me. He never physically hurt me the way he has to Sirius and Regulus, but I am apart of the Noble House of Black. We have to live up to certain standards. Getting sorted into Slytherin is apart of that. I do not even want to know what is going to happen tomorrow when my oldest brother does not get sorted into Slytherin. Winter break is going to be interesting...

I am brought back from my thoughts when Regulus says goodnight to me. I leave his room and get back into my bed and fall asleep.

end of flashback

"You will get sorted into Slytherin, you hear me, son," my father tells Sirius knowing very well that his eldest will not be sorted into Slytherin.

"Of course father, why wouldn't I want to get sorted into the house of snakes?" Sirius sarcastically replies.

"Well, you know what the consequences will be if you are sorted into Gryffindor,"

Mother interrupts before the two have a chance to raise their voices and cause a scene "Goodbye Sirius, make sure to write" and gives him a quick hug and sends him off.

The four of you leave platform 9 3/4 and return home. A couple of hours later a white-spotted, black owl, that you recognize to be my cousin's, Narcissa Black, flies through the window and drops off a letter. "Mum, Dad, Reg! Cissy wrote" I yell.

"What did we talk about yelling throughout the house Cassieopia," dad says sternly. "Sorry father, I was just excited" I shyly respond.

By this time Mum and Reg are in the living room with us.

"Well open it, Cass," Mother tells me. I open the leader and read it to them.

Uncle Orion, Aunt Walburga, Regulus, and Cassiopeia,

I feel as though Sirius will not write to tell you how the sorting ceremony went, so I took it upon myself to write. Sirius was sorted into Gryffindor.

Narcissa Black

I look up from the letter only to see my father fuming and mother looking disappointed. After a couple of seconds of silence, father says "You too will get sorted into Slytherin, we cannot have any more disappointments as children. You understand."

"Yes, father" Reg and I say simultaneously.

"Good now go to bed, I need time to think." Reg and I walk upstairs and walk to our designated rooms.

I plop onto my bed and fall asleep terrified for what is going to happen to Sirius when he comes home.


	3. Yule of 1971

Cassiopeia pov:

Today, Sirius comes back home from Hogwarts. All honestly I am scared for him. Mum and Dad have gotten stricter with Reg and me because of Sirius being sorted into Gryffindor. A week ago I woke up at 9 am instead of 7 am like I was supposed to and I got a lecture about how 'no man wants a wife who wakes up that late' ugh so annoying.

The front door opened to expose an annoyed and grinning Sirius Black. Upon seeing my brother I run up and give him a big hug, smiling into his shoulder I whisper "I missed you"

"I missed you too, Cass," Sirius says, releasing from the hug. "I missed you too brother," Sirius says, messing up Reg's hair. Reg quickly fixes his hair while mumbling a quick "missed you too"

Mum and dad do not look as excited, in fact, they look angry.

"Regulus and Cassieopia go to your rooms," dad says. Reg and I go up to his room and can hear the yelling coming from Mum, Dad, and Sirius.

We can't hear the whole conversation, but bits like 'You're a disgrace' 'how dare you' 'shame' 'filthy blood traitor' 'mudbloods' 'no respect'

Sitting on Regulus's bed I lean my head on his shoulder. After half an hour of screaming, there is silence. "I think they're done," Reg finally says.

Not a minute later, Mum opens the door and says, "Dinner is ready"

We walk down and take our respective seats at the table. Dad and one end, mother at the other; and Sirius on one side, and Reg and I on the other. Kreature walks in and hands us the food.

"Thank you Kreature," I tell him.

"Of course! Anything for young Mistress Black!" Kreature replies with eyes full of appreciation and love. Despite what Sirius says, Kreature is a good elf. It is not difficult to make him like you. You just have to be considerate and nice to him.

Dinner is filled with awkward silence until dad decides to speak.

"Did you know your brother befriended a blood traitor and mudblood" he looks over at Reg and me to see our reaction?

A look of pure shock. What was my brother thinking? All honestly I could care less about blood status, but I would never openly admit that to everyone. The consequences are too severe. He could be disowned! Like cousin Andy, she married a mudblood.

"A mudblood? You're joking right?" I respond after 30 seconds of silence.

"Of course not sister" Sirius responds with a smirk. IDIOT. My brother is an idiot. That Griffindor courage is going to get him disowned.

The rest of the dinner is spent in complete silence.

After dinner, our parents dismiss us up to our rooms. I quickly get ready for bed then go into Sirius's room

"Sirius you bloody idiot! Are you trying to get yourself disowned?! Why would you befriend a mudblood! I mean blood traitor I get, your a Gryffindor, and that house is full of them. But mudblood?! Are you serious?! No wonder you weren't sorted into Slytherin! Where is your self-preservation?!" I yell at my idiotic brother.

"Yes, I am Sirius" a smirking Sirius responds.

I wack him on the head, "I am being serious!" before he makes the dumb remark I give him a death glare and say "Don't you dare"

Sirius goes and sits on his bed and pats it indicating for me to sit too. I go and sit next to him and he starts to talk. "You don't get it." I look at him curiously but let him continue. "I never fit in in this family. I mean mother and father always hated me even before I got sorted into Gryffindor" I'm about to interject when he gives me a look and says, "don't even try to defend them. I mean it is obvious that Reggie is mother's favorites and you are fathers. And you and Reggie are closer with each other because of the twin thing, you guys like read each other's minds or whatever." I look at him empathetically and let him continue. "I'm never going to have that and I'm okay with that. This place has never been my home. But Hogwarts is. I have friends there, the blood traitor father was talking about either is James, James Potter. He's my best friend." Sirius smiles thinking about him, which in turn makes me smile. "And the muggle-born, not mudblood, that is an offensive term, is Lily Evans, James is in love with her and thinks he's going to marry her when he's older" he chuckles at this "she's one of the smartest witches in my year you know." 

"I'm sorry" Sirius looks at me confused "for yelling at you before... I should have let you explain instead of jumping to conclusions," I elaborate. 

Sirius smiles and says, "Hogwarts is amazing you know. Besides James and Lily, there's Peter and Remus. They're amazing and the castle is incredible. You'll love it." 

"I can't wait till September, then Reg and I get to go," I say smiling at my big brother. He goes and hugs me. 

"Will you still talk to me when I'm sorted into Slytherin?" I ask.

"Whose saying you're going to get sorted into Slytherin," my brother says. I look at him as if he completely lost his mind.

"Where else would I get sorted? There's no way I'm being sorted into Gryffindor" I respond.

"There's Hufflepuff. You know you are very loyal," I laugh at my brother's statement. 

"Yes, because father's little princess would get sorted into Hufflepuff, they're a joke," I say laughing at how my brother could even say such a thing. 

"You never know" I roll my eyes at this response and get up and head towards the door. 

"Goodnight Sirius" "Goodnight Cass," I leave his room and go into my room where I drift to sleep.

25 December 1971

I wake up extra early because it is Yule and who doesn't love Yule. I can only hope that today is less awkward but knowing my family it will be filled with arguing. I get up and change into presentable clothes and go to wake up Reg, Sirius, then Mum and dad.

"Reg... Reggie... REGULUS," I say while shaking him trying to wake him up. Finally, after I scream Regulus he wakes up. "It's Yule, get up I want to open presents" after another minute of annoying him he gets up and we proceed to wake up who was much easier to wake than Reg.

"Come one now we have to wake up Mum and Dad," I say

"Count me out. I don't want to deal with those devils this early in the morning" Sirius says

I give him a dirty look and decide not to protest. I open the door to their room and go over to dad's side of the bed since I have less of a chance of getting in trouble.

"Dada... It's Yule" I say shaking him lightly. He wakes up instantly and smiles at me.

"Good morning princess," my dad says and wakes up mum who's slightly upset that she was woken up this early. Nevertheless, the five of us head downstairs and open our presents.

The day was enjoyable. Sirius and mum and dad didn't even fight.


	4. Summer of 1972

Cassiopeia POV:

Sirius returned home from Hogwarts for the holiday. Mum and dad pestered him non-stop about living up to being the 'heir of the Noble House of Black' and everything that it entails also known as everything Sirius despises. Mum, Dad, and Sirius just had a heated argument about the people Sirius associates himself with and Sirius left and went up to his room.

I knocked on his door and when there was no response I opened it slowly and let myself in.

"Sirius, you okay?" I ask calmly

"I'm fine Cass"

"No you're not, don't lie to me," I say, walking over and sitting next to a teary eye Sirius.

"I just don't get why they make such a big deal of who I associate myself with. They're good people they really are, and muggleborns aren't bad like they told us. I can't wait for you to meet my friends"

"Sirius... We both know that I can't be friends with your friends. I'm most likely going to be sorted into Slytherin and unlike you, I can't associate myself with non-pure bloods." Sirius gives me a sad look.

"I'm sorry that was harsh... I just can't Sirius, Mum and Dad wouldn't approve, Reggie wouldn't either. I just can't. aim really sorry, they sound lovely though" I respond sadly

"It's okay, I get it... maybe we can secretly meet up so you can at least meet them," he asks hopefully

"That sounds lovely" I smile and hug Sirius goodbye before I go and get up to go back to my room.

"Goodnight Sirius"

"Goodnight Cass"

Next Morning

I wake up, get dressed, then head downstairs for breakfast. 

Upon entering the dining room I see Mum, Dad, and Reggie, I smile and say, "Goodmorning Mum, Dad, Reggie" 

"Morning Princess" my Dad responds with a smile

"Morning Cass," Reg says

"Morning Cassieopia" Mum responds

"Where is Sirius, he was supposed to be downstairs already" Mum complains

"I don't know," I say while sitting down in my assigned seat next to Reggie. "Maybe he is still asleep, do you want me to wake him up?" I ask Mum.

"No darling, I'll have Kreature do it," Mum replies

"KREATURE" Mum yells and Kreature pops into the dining room

"Yes mistress, what can Kreature do for a mistress?" Kreature asks

"Go and wake up Sirius and tell him it's time for breakfast"

"Yes, mistress" and with that Kreature pops and goes and wakes up Sirius.

A couple of minutes later Sirius comes down. 

"Well look who decided to grace us with his presence," Mum sarcastically says while rolling her eyes. 

"Well, it was a hard decision, but of course I wanted to see my loving, caring family" Sirius responds.

"Don't sass your mother" Father says sternly 

"Whatever" Sirius rolls his eyes and sits down and we start to eat. 

"So, tomorrow is the big day, my babies are going to Hogwarts," Mum says full of pride.

"Yes, finally someone who isn't a disgrace to the Black will be at Hogwarts representing our family," Dad says.

I choose to ignore Dad's comment and respond with, "I can't wait. Can you tell me about the common room again Dad pleaseeee," I say with puppy dog eyes

My dad chuckles a little and responds with, "Of course princess" I smile and let him talk.

"The common room is beautiful, it's in the dungeons and you can see inside the black lake. Your head of house, Slughorn is a good friend of mine. He takes a liking to Mudbloods, but I suppose he has to because he teaches them and whatnot. Anyway, the interior is much like the Black Manor in the sense of the darker interior." 

"You speak like she's already in Slytherin," Sirius scoffed at his mention of the house.

Dad stands up angrily and says, "I know my daughter and son will get sorted into Slytherin because unlike you they will make us proud and live up to the Noble House of Black's name" Mum puts her hand on his shoulder in an attempt to calm him down. Father sits back down and continues to eat. 

"Don't worry father, Cass and I will make you proud" Reg responds.

"I know you will sweetie," Mum says. Dad nods in agreement. 

The day continues with more bickering from Mum, Dad, and Sirius. 

Tomorrow we leave for Hogwarts and, to be honest, I am terrified that I won't get sorted into Slytherin. Anyway, I double-check everything is packed and go to sleep.


	5. Year 1

1972

Cassiopeia Black age 11

Regulus Black age 11

Sirius Black age 12


	6. Hogwarts

Cassiopeia Pov:

Today is the day we leave for Hogwarts. I am terrified but at least I have Reggie and kind of Sirius. I know I won't be able to speak to my eldest brother because of dumb house rules and whatnot but I still have my twin.

I look at myself in the mirror making sure I look reasonable, I am wearing a basic black summer dress.

"Cass come one we're about to leave" I hear my Mum yell from downstairs

"Coming" I grab my bags and head downstairs

"Good, now that we are all here we can apparate to the platform," Dad says.

Sirius and I hold on to one of Dad's hands and Reg holds onto Mum's hand.

We apparate directly onto the platform because Mum and Dad don't want to see any more muggles than they have to.

"Goodbye, my loves" Mum says and hugs Reg and me.

"Goodbye kids," Dad says with a nod.

"Sirius doesn't disappoint us more than u have already and become friends with the Avery kid, he'll be a good influence on you," Mum says

"Yeah, I'll pass but thanks for the suggestion," My idiot brother said.

"Respect your mother boy," dad says sternly. Sirius just rolls his eyes in response. We hear the train horn and quickly finish our goodbyes.

"Goodbye, Mum and Dad" Reg and I say simultaneously.

"Make sure to get into Slytherin," Dad says. With one last wave, the three of us go and board the train.

"You can sit with my friends and me if you want," Sirius says

"Yeah we'll pass on sitting with blood traitors and mudbloods," Reg responds for both of us.

"What about you Cass," Sirius asks

"Erm, I'll just go with Reggie, bye" Sirius goes and walks off to find his friends, and Reg and I go and make our way towards the Slytherin compartment and find an empty compartment. We find one quickly and take our seats.

"Hello I'm Estella Zabini, can I sit here?" she asks.

"Blood status?" my twin asks

"Pureblood" she responds with. Reggie nods and she sits down next to me, and from Reg.

"Black, Cassiopeia Black," I say and hold my hand out for her to shake.

"Regulus Black," Reg says.

"Nice to meet you," she says. Reg nods and responds with

"So what house do you think you get sorted into?"

"Slytherin mostly likely. You?" she asks

Reggie scoffs and responds with "Slytherin obviously"

"Please excuse my twin" I saw while kicking his leg "He seemed to have left his manners back at the manor," I say, giving him a stern look. Before anyone can answer the door opens again to reveal and girl.

"Hello, can I sit here, I really don't want to sit my brother," she says giggling.

Before my arrogant twin can respond I say, "Of course" "I'm Black, Cassiopeia Black and this is my twin Regulus and this is Estelle Zabini, and you are"

She sits next to Reg and says, "Chandler Greengrass"

The whole way to Hogwarts we discuss different topics that are pureblood okay. We change into our robes and get into the boats.

We enter the Great Hall and it is definitely called the Great Hall for a reason. My eyes drift over to the Gryffindor table where my eyes meet my brothers. He gives me a thumbs up and I smile back. He's sitting with 3 other guys. I make eye contact with one of them, but he looks away quickly.

Professor McGonagall starts to call first years up to the sorting hat.

"Black, Cassiopeia" I hear her call.

I walk up and sit on the chair and McGonagall puts the hat on my head.

"hmmm very loyal... perhaps Hufflepuff"

"Please no, Please Slytherin Pleaseeee"

"ambitious and cunning"

"Yes Slytherin please... please just say Slytherin"

"Let it be... SLYTHERIN"

The Slytherin table claps and the Gryffindor table 'boos'

I hop off the stool and my eyes meet my eldest brother who looked disappointed. I shake it off and look at my twin who smiles and gives me a nod. I go and sit down next to a second year.

"Black, Regulus" McGonagall calls out

Regulus walks up to the stool and the hat yells 

"SLYTHERIN"

He comes and sits next to me.

"Regulus Black" my brother greets the boy sitting next to me.

"Severus Snape" he responds

"Cassiopeia Black," I say shaking his hand.

"Carrow, Alecto" McGonagall calls

"SLYTHERIN"

"Carrow, Amycus"

"SLYTHERIN"

"Greengrass, Chandler"

"SLYTHERIN"

"Zabini, Estelle"

"SLYTHERIN"

Estelle sits next to Reg and me, and Alecto, Amycus, and Chandler sit across from us.

After dinner, we go, led by the 5th year prefects to the dungeons where the common room is located.

"Reggie, it's even more beautiful than dad said," I say to my brother.

He laughs and says, "The only person I've met who cares so much for the aesthetic of things" I roll my eyes in response.

"Boy dorms to the right and girl dorms to the right," The girl prefect says.

"Remember the password is 'pureblood,' now off to bed, breakfast is at 8," The boy prefect says.

I bid my goodbyes to my twin and go to my dorm.

I walk in and see 4 beds, I take the one closest to the bay window. Following in suit are Chandler, Estelle, and Alecto. 

"Well, at least we are all purebloods," Chandler says. We all nod in agreement. 

"Goodnight girls," I say and chorus goodnights back.


End file.
